U.S. patent number 4,509,504 [Application Number 06/079,951] was granted by the patent office on 1985-04-09 for occlusion of body channels.
This patent grant is currently assigned to Medline AB. Invention is credited to Jan-Olof Brundin.
United States Patent |
4,509,504 |
Brundin |
April 9, 1985 |
Occlusion of body channels
Abstract
A method for obstructing channels, ducts and other hollow spaces
in human and animal bodies is disclosed comprising inserting a
device having a portion thereof adapted to swell at least 20% in
size when in contact with the fluid of the human or animal body,
the device being in a shape matching and cooperating with the
channel to be obstructed.
Inventors: |
Brundin; Jan-Olof (Lidingo,
SE) |
Assignee: |
Medline AB (Stockholm,
SE)
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Family
ID: |
26762598 |
Appl.
No.: |
06/079,951 |
Filed: |
September 28, 1979 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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870595 |
Jan 18, 1978 |
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Current U.S.
Class: |
128/831; 128/843;
128/899 |
Current CPC
Class: |
A61K
9/0039 (20130101); A61F 6/225 (20130101) |
Current International
Class: |
A61K
9/00 (20060101); A61F 6/00 (20060101); A61F
6/22 (20060101); A61B 017/00 () |
Field of
Search: |
;128/325,130,131,341,138R,1R,285,294 ;604/55 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Thaler; Michael H.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation-in-part of my earlier application Ser. No.
870,595 filed Jan. 18, 1978, now abandoned.
Claims
What is claimed is:
1. A method of occluding a body reproduction duct of an animal
comprising the steps of
(1) inserting a water-swellable contraceptive hydrogel article into
said body reproduction duct;
(2) bringing said hydrogel into contact with animal tissue
fluid;
(3) allowing said hydrogel to swell to an extent of at least 40% up
to 300% of its original size and thereby
(4) contacting and impinging upon the body duct in which said
device is inserted,
said device being substantially completely inert to said body fluid
and the body tissue with which it is in contact, having a
cross-sectional configuration corresponding to that of said
reproduction duct and an indicator removal thread secured
thereto.
2. The method according to claim 1 including the additional step
of:
(5) removing the thus-inserted hydrogel article.
3. The method according to claim 1 wherein said body reproduction
duct is a fallopian tube and said article has a substantially
circular cross-sectional configuration.
4. The method according to claim 3 wherein said article is in the
form of a drop having a diameter of approximately 0.8 mm prior to
swelling.
5. The method according to claim 3 wherein said article is
substantially in the form of a cylinder slightly tapering towards
the ends.
6. The method according to claim 1 wherein said hydrogel is a
cross-linked, water-swellable copolymer of a hydrophilic hydrogel
and nylon-6 as a hydrophobic monomer.
7. The method according to claim 1 or 6 wherein said device
includes anchoring means to at least temporarily secure the device
when implanted to said body reproduction duct.
8. The method according to claim 7 wherein said anchoring means
includes a pair of fixed triangular shaped, pointed projections
extending beyond the outer surface of the unswollen hydrogel prior
to step (3).
9. The method according to claim 7 wherein said anchoring means is
a pair of fixed, pointed projections of nylon-6 cross-linked to
said hydrogel.
10. The method according to claim 1 wherein said device includes a
visually observable removal thread one end being embedded into said
hydrogel.
11. A method for at least temporarily occluding a reproductive
oviduct or spermatic duct of an animal for contraceptive purposes,
said method comprising the steps of:
(a) forming a body of water-swellable polymeric hydrogel to the
extent of at least 20% in volume by absorbing water, said hydrogel
being substantially inert to body fluid and the tissue of said
reproductive duct;
(b) shaping said hydrogel body into a cross-section which in the
dry state is no larger than about the size of the cross-section of
the reproductive duct;
(c) inserting the shaped hydrogel body in the dry state into the
reproductive duct at a predetermined distance from the opening of
the duct; and
(d) allowing the thus inserted shaped hydrogel body to remain in
position, absorb water from the body fluid thereabout and anchoring
itself by pressure against the surrounding walls of the duct.
12. The method according to claim 11 wherein said hydrogel swells
to the extent of up to 300% and is substantially inert to both said
fluid and the surrounding tissue of said duct.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a device for temporary or
permanent occlusion of channels or hollow spaces in human or animal
bodies, particularly oviducts and spermatic ducts. The invention
also includes a method of occluding a body reproduction channel by
inserting a device of the type herein described.
Human and animal bodies contain a vast number of channels or
vessels, through which fluid and/or other substances or objects can
pass or be transported. In certain cases, it is desirable to
disrupt such a passage. As an example, for contraceptive purposes
the spermatic ducts and the oviducts or fallopian tubes can thus be
occluded such that by the passage of sperms and ova, respectively,
are prevented. In certain vascular diseases, for instance, it may
be desired to stop the flow of blood through certain blood vessels.
This is possible both on the arterial and veinous side of the
circulatory system. Methods previously used for this purpose have
had disadvantages such as, for instance, that the passage through
the channel has been difficult to occlude completely, difficulty in
reopening, when desired, and the like.
DETAILED DESCRIPTION OF THE INVENTION
It has now been found that these and other disadvantages can be
eliminated by using a device consisting of a material, which when
contacted with a body fluid, such as physiological fluids and
blood, swells at least 20% in volume. Apart from this swelling, the
device introduced must be substantially completely inert to the
body fluids and to other surrounding body tissues. The amount of
swelling of the device in contact with the body fluid is preferably
at least 40%, more preferably at least 80% and may well be in the
range between 20 and 300% depending on the swellable material
employed, amount of fluid to which the device is exposed and the
like. The channels in human beings and animals, which can be
occluded by this device include blood vessels, urethers, spermatic
ducts and oviducts as examples.
As used herein the dry state of the device means the condition of
the device prior to contact with physiological fluids. It will be
appreciated that the device itself may contain molecules of water
trapped within a gel-like framework of polymeric bonds. This state
is also referred to herein as non-hydrated. When contacted with the
body fluids the device will become hydrated and swell to the extent
indicated below.
The exact geometric form of the device is not critical and is
conveniently essentially cylindrical, spherical or egg-shaped or
may take the form of a teardrop. In certain instances the devices
is preferably in the form of an hour-glass. However, generally the
device will have a circular cross-section in that portion
corresponding to and cooperating with that portion of the channel
to be occluded. This cross-section of the device when in the dry
state is preferably smaller than the cross-section of the channel
to be occluded such that the device can conveniently be introduced
along the channel and accurately positioned well before swelling is
complete.
The device according to the invention is particularly suited for
use as a contraceptive device and this is especially adapted for
practicing a contraceptive method. According to this aspect of my
invention the device is inserted into and positioned within the
appropriate location in the spermatic ducts or the oviducts. The
device is in this case preferably provided with an attached thread
or string in such a way that it can be conveniently withdrawn
usually without a surgical incision. This thread can be made of an
X-ray opaque material enabling the physician to localize and
determine the position of the device within the duct. The device
itself can also contain X-ray contrast substances or materials
which are themselves known.
When in contact with the fluid of the human or animal into which
the device is inserted, the material of the device swells at least
20%, preferably at least 40%, more preferably at least 80%, and may
even swell as much as 300%. In other respects, the material should
be essentially inert and harmless to the body fluid and surrounding
tissues and should remain intact, that is, should not be absorbed
by the human or animal body into which the device is inserted.
Suitable materials for this purpose are hydrogels, i.e.
water-containing gels. Preferred hydrogels are polymers and
copolymers of the acrylic type such as cross-linked polyacrylamide
and polymers and copolymers of acrylic and methacrylic esters
having at least one hydroxy radical in the side chain. A preferred
monomer is 2-hydroxy-ethyl-methacrylate; other preferred monomers
are monometharylic esters of di- or triethylene glycol of
2,3-dihydroxypropane. As cross-linking agents polyfunctional
acrylates, such as the esters of the same glycols, e.g. ethylene
glycol-bis-methacrylate, are useful. Materials useful in accordance
with the present invention as well as a process for their
preparation are described in the U.S. Pat. No. 3,943,045 issued
Mar. 9, 1976, the disclosure of which is hereby incorporated by
reference.
The device in the dry state should be essentially elastic and
plastic only to a very small extent. In its unswollen or
non-hydrated state it may be rigid, stiff or hard, but should
preferably soften upon swelling. The device can contain a
reinforcing material, an armouring material if desired.
In use, the device according to the invention in the unswollen
state, is introduced into a body channel, i.e. a natural or
pathological hollow communication in the human or animal body,
which can also be described as a hollow space, and will thereafter
swell, when in contact with the body fluid, either human or animal,
so that the device which can pass through the channel when
inserted, will swell and effectively engage the walls of the
channel. Through the pressure then exerted by the channel walls on
the device, it will be slightly compressed simultaneously with a
possible expansion of the elastic walls of the channel and swelling
of the device as well. In this way the device occludes the entire
cross-section of the channel and prevents anything from passing
through the channel while at the same time the device is firmly
anchored in position.
After insertion into an oviduct and expansion, the passage of ova
to the uterus and spermatozoa, respectively, upwards through the
oviduct to the unfertilized ovum will be prevented. After occlusion
of the spermatic duct the outward passage of the spermatozoa will
be prevented and a good contraceptive action is achieved. If
desired, the inserted bodies can be withdrawn by surgical procedure
or, as is the case when inserted in an oviduct, by extraction
through the uterus when the device is provided with an attached
thread for extracting the device.
Thus according to the method aspect of my invention an intra-tubal
device (ITD) of a hydrogel of the type described is inserted into
the transsectional star-shaped channel and positioned in the
intramural part of the oviduct. A hysteroscope is used to guide and
follow the insertion procedure. The muscular wall of the tube is
distensible and in cross-section becomes round shaped; this is
clearly visible during hysteroscopy. Thus to fully occlude the
luminal passage the intra-tubal device has an essentially round
cross-section thereby maximizing the area over which the surface of
the device is in contact. Upon contact with the body fluids the
hydrogel swells causing elongation and further contact. Contact is
also enhanced by the softness of the porous surface of the swollen,
hydrated device.
In order to fully secure the exact position of the device, prevent
early expulsion and reatin it in the desired position, it is
preferred to employ one or more anchoring means, sometimes in the
form of protruding wings and preferably of a physiologically inert
but essentially non-swellable material. This wing approach is
especially preferred in that the swelling process of the hydrogel
takes place after insertion of the device. This results in a
reduction of the length of the free ends of the projecting wings
which, in turn, minimizes the damage that could be expected by the
wing ends on the tubal wall.
It has been found that the rate of expulsion of hydrogel-type
intra-tubal devices is greatest shortly after insertion and that
this rate decreases as a function of time, presumably as the
hydrogel becomes fully hydrated and swells to occlude and be
retained in the tube. The anchoring wings provide a means to retain
the device in place upon insertion and continue to effectively
function for a period of time until the hydrogel is substantially
completely hydrated and swollen to its maximum obtainable size.
BRIEF DESCRIPTION OF THE DRAWINGS
The device according to the invention will now be described in more
detail referring to an embodiment used as a contraceptive inserted
in the fallopian tube. In the drawings:
FIG. 1 is a sectional view of a preferred embodiment of the
invention as a contraceptive device for insertion into the
fallopian tube.
FIG. 2 is a partial view of FIG. 1.
FIG. 3 is a view of another embodiment also useful as a
contraceptive device for insertion into the fallopian tube.
FIG. 4 is a schematic and partially sectional view of a uterus also
showing the fallopian tube, the ovaries and part of the vagina.
FIG. 5 is a perspective end view of FIG. 6, and
FIG. 6 is a sectional view of another preferred embodiment of the
device of the present invention having anchoring wings for
insertion into a fallopian tube and useful as a contraceptive
device.
DETAILED DESCRIPTION OF THE DRAWINGS
In FIG. 1 a thread 1 of nylon-6 is fastened to a body 2 of
polyvinyl pyrrolidone by graft polymerizing vinyl pyrrolidone onto
the thread. The body 2 is in the form of a drop. The diameter of
the drop is approximately 0.8 mm in the unswollen, unhydrated
state. In the swollen, fully hydrated state this diameter is
approximately 1.45 mm.
FIG. 2 shows the thread 1 of the device according to FIG. 1. An
X-ray opaque ring 3 is embedded in the end of the thread 1.
Additionally, the thread end is provided with a loop 4, which also
can be of an X-ray opaque material if desired, but is preferably
part of the nylon thread itself in order to better secure the nylon
thread to the body. The embodiment of FIG. 3 also contains a thread
1 of nylon embedded in a suitable length of the body 2 of hydrogel
which is preferably polyvinyl pyrrolidone. In this embodiment the
cross-section is circular and the hydrogel body 2 is to a length of
about 7-11 mm, for instance, extended. The configuration of FIG. 3
can be used in the same way as the embodiment of FIG. 1 having
about the same cross-sectional diameter.
FIGS. 5 and 6 illustrate preferred embodiments of the invention
similar to FIG. 3 in configuration having a hydrogel portion 2 of
about 11 mm, a circular cross-section of about 1.6 mm tapering
slightly to the bulbous end of about 1.4 mm. A nylon thread 1 is
secured to the inner portion along the central axis of the hydrogel
2 and a pair of opposing nylon anchoring means in the form of wings
7 are secured to the nylon string 1 and extend in opposite
directions. The anchoring wings 7 have a generally triangular shape
when viewed from the end of the device as shown in FIG. 5 and are
used to retain the device when implanted into the surrounding
fallopian tube. It will be understood that one, two or several of
such anchoring means may be used. Also differing shapes and
configurations may be used as well, the specific shape and
dimensions of the device of FIG. 1 being illustrative. The
embodiment of FIGS. 5 and 6 may be fitted with an X-ray opaque ring
and thread arrangement as shown in FIG. 2 or the hydrogel 2 may
include an X-ray opaque material dispersed therein.
The body-cavity occluding portion of the device can preferably be
made of a polymer of vinyl pyrrolidone and nylon in which liquid
nylon or bulk nylon is polymerized with vinyl pyrrolidone, the
nature of the reaction possibly being a graft polymerization or
polymerization followed by cross-linking. The resulting material
may be termed a hydrogel. This material behaves as comprising a
skeleton made by hydrofobic material. Using such a material, the
swelling and the water absorption power may be altered by changing
the amounts of nylon and vinyl pyrrolidone to be polymerized. As an
example, three (3) parts vinyl pyrrolidone and 1 part nylon forms a
polymer having an expansion factor of 1.48, that is swells 48% in
water, with a water content of 66%; five (5) parts vinyl
pyrrolidone and 1 part nylon forms a polymer having an expansion
factor of 1.78 with a water content of 78%. Other variations in
monomer proportions will produce corresponding changes in the
properties of the resulting hydrogel and are easily determined by
the skilled worker. This embodiment comprising a skeleton
(backbone) has an increased tenacity so that it easily can be
withdrawn from the fallopian tube by means of the threads. This
advantage is also obtained by a device containing a reinforcing
material. However, the non-reinforced hydrogel having no backbone
of hydrofobic material is not sufficiently tough, so that the
withdrawal often fails by rupture of the device. The initial
material is usually in the form of a viscous fluid which is
injected into a mold of the desired configuration, as in FIGS. 1, 3
or 5, and copolymerized by gamma irradiation or heat.
FIG. 4 illustrates placement of a device according to the invention
for use as a contraceptive in the oviducts. The device 2 is
inserted from the uterus 5 through the openings of the oviducts 6
into the uterus. As shown in the figure, the body 2 is in contact
with the walls of the oviducts 6 along the entire length of the
device and follows completely and cooperates with the shape and
motion of the oviduct. The device 2 to the left side of the drawing
is provided with a long thread 1 so that it can be checked at the
cervix uteri to confirm that the device still is in place.
My invention also includes a method for occluding the fallopian
tubes by inserting a device of the type described into the
appropriate position in the oviduct. A hysteroscope or similar
device is employed in which each oviduct opening into the uterus is
located and the device is implanted. Upon contact with the body
fluids the hydrogel swells to a factor of from 20 to 80%, possibly
up to 300% of its original size. The potential difficulty of
expulsion of the device is substantially reduced or completely
eliminated by the use of anchoring means of the type shown in FIG.
5. The hydrogel of the device, once inserted, swells over a period
of time, typically in a week or so depending on the monomer mixing
ratio and other factors, to its full, swollen size. Swelling force
against the intramural wall is then maximized and the device is
retained in place.
Using a device of the type described herein with anchoring means,
an embodiment of which is illustrated in FIG. 5, several advantages
are obtained. Firstly, with respect to manufacture, if the
anchoring wings are nylon, preferably nylon-6, the anchoring wing
can be used to attach to the retrieval thread 1 providing a more
substantial bond as between the thread and the surrounding
hydrogel. In the manufacturing process the gamma irradiation, as
above described, causes the hydrogel to co-polymerize with the
nylon-6 material of the anchoring wing. Secondary advantages are
realized upon insertion of the anchoring-type device. The swelling
process of the hydrogel occurs after insertion of the device which
reduces the extent of protrusion of the anchoring wings by
increasing the cross-sectional swelling of the hydrogel. This
minimizes any damage caused by the wings to the tubal wall as the
anchoring purpose of the wing or wings is gradually replaced by the
swelling of the hydrogel of the device. The surface of the swollen
hydrogel becomes porous and cooperates with the tubular wall in
which the device is inserted.
It has been determined that intra-tubal devices of the type
described are well tolerated by animal tissue. Devices of the type
shown in FIG. 5 have been tested in paravertebral muscles of the
rabbit and tissue reaction was compared to that of USP negative
control plastic according to the procedure of Turner et al, J.
Biomed. Mater Res. 7:39 (1973). Despite swelling of the hydrogel,
which apparently exerted pressure upon the surrounding tissue, no
severe tissue reaction was observed. The degree of tissue necrosis,
inflammation, the invasion of polymorphs, eosinophils, macrophages,
plasma cells, fibroblasts or edema produced by the hydrogel were
not different from that produced by the USP negative plastic. Tests
have also been conducted and except for disappearance of the thin
intramural mucosa and a slight edema in the tubal wall, no
pronounced damage was observed after a period of ten days.
Follow-up studies and observations are continuing.
Even though the device according to the invention has been
primarily described in the form of a contraceptive, it is
understood that other medical applications of the device can be
made, for instance, in the case of brain damage, such as cerebral
haemorrhage, or when treating varicose veins. In such applications
the device according to the invention is inserted in the
appropriate vessel to completely obstruct that vessel. For certain
circulatory applications an hour-glass form is preferred.
* * * * *